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      1 /*
      2  * Copyright (C) 2016 The Android Open Source Project
      3  *
      4  * Licensed under the Apache License, Version 2.0 (the "License");
      5  * you may not use this file except in compliance with the License.
      6  * You may obtain a copy of the License at
      7  *
      8  *      http://www.apache.org/licenses/LICENSE-2.0
      9  *
     10  * Unless required by applicable law or agreed to in writing, software
     11  * distributed under the License is distributed on an "AS IS" BASIS,
     12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     13  * See the License for the specific language governing permissions and
     14  * limitations under the License.
     15  */
     16 
     17 package android.media;
     18 
     19 import android.os.Handler;
     20 import android.os.Looper;
     21 
     22 /**
     23  * AudioRouting defines an interface for controlling routing and routing notifications in
     24  * AudioTrack and AudioRecord objects.
     25  */
     26 public interface AudioRouting {
     27     /**
     28      * Specifies an audio device (via an {@link AudioDeviceInfo} object) to route
     29      * the output/input to/from.
     30      * @param deviceInfo The {@link AudioDeviceInfo} specifying the audio sink or source.
     31      *  If deviceInfo is null, default routing is restored.
     32      * @return true if succesful, false if the specified {@link AudioDeviceInfo} is non-null and
     33      * does not correspond to a valid audio device.
     34      */
     35     public boolean setPreferredDevice(AudioDeviceInfo deviceInfo);
     36 
     37     /**
     38      * Returns the selected output/input specified by {@link #setPreferredDevice}. Note that this
     39      * is not guaranteed to correspond to the actual device being used for playback/recording.
     40      */
     41     public AudioDeviceInfo getPreferredDevice();
     42 
     43     /**
     44      * Returns an {@link AudioDeviceInfo} identifying the current routing of this
     45      * AudioTrack/AudioRecord.
     46      * Note: The query is only valid if the AudioTrack/AudioRecord is currently playing.
     47      * If it is not, <code>getRoutedDevice()</code> will return null.
     48      */
     49     public AudioDeviceInfo getRoutedDevice();
     50 
     51     /**
     52      * Adds an {@link AudioRouting.OnRoutingChangedListener} to receive notifications of routing
     53      * changes on this AudioTrack/AudioRecord.
     54      * @param listener The {@link AudioRouting.OnRoutingChangedListener} interface to receive
     55      * notifications of rerouting events.
     56      * @param handler  Specifies the {@link Handler} object for the thread on which to execute
     57      * the callback. If <code>null</code>, the {@link Handler} associated with the main
     58      * {@link Looper} will be used.
     59      */
     60     public void addOnRoutingChangedListener(OnRoutingChangedListener listener,
     61             Handler handler);
     62 
     63     /**
     64      * Removes an {@link AudioRouting.OnRoutingChangedListener} which has been previously added
     65      * to receive rerouting notifications.
     66      * @param listener The previously added {@link AudioRouting.OnRoutingChangedListener} interface
     67      * to remove.
     68      */
     69     public void removeOnRoutingChangedListener(OnRoutingChangedListener listener);
     70 
     71     /**
     72      * Defines the interface by which applications can receive notifications of routing
     73      * changes for the associated {@link AudioRouting}.
     74      */
     75     public interface OnRoutingChangedListener {
     76         public void onRoutingChanged(AudioRouting router);
     77     }
     78 }
     79